Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * main.c
4 : * Stub main() routine for the postgres executable.
5 : *
6 : * This does some essential startup tasks for any incarnation of postgres
7 : * (postmaster, standalone backend, standalone bootstrap process, or a
8 : * separately exec'd child of a postmaster) and then dispatches to the
9 : * proper FooMain() routine for the incarnation.
10 : *
11 : *
12 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
13 : * Portions Copyright (c) 1994, Regents of the University of California
14 : *
15 : *
16 : * IDENTIFICATION
17 : * src/backend/main/main.c
18 : *
19 : *-------------------------------------------------------------------------
20 : */
21 : #include "postgres.h"
22 :
23 : #include <unistd.h>
24 :
25 : #if defined(WIN32)
26 : #include <crtdbg.h>
27 : #endif
28 :
29 : #if defined(__NetBSD__)
30 : #include <sys/param.h>
31 : #endif
32 :
33 : #include "bootstrap/bootstrap.h"
34 : #include "common/username.h"
35 : #include "port/atomics.h"
36 : #include "postmaster/postmaster.h"
37 : #include "tcop/tcopprot.h"
38 : #include "utils/help_config.h"
39 : #include "utils/memutils.h"
40 : #include "utils/pg_locale.h"
41 : #include "utils/ps_status.h"
42 :
43 :
44 : const char *progname;
45 : static bool reached_main = false;
46 :
47 :
48 : static void startup_hacks(const char *progname);
49 : static void init_locale(const char *categoryname, int category, const char *locale);
50 : static void help(const char *progname);
51 : static void check_root(const char *progname);
52 :
53 :
54 : /*
55 : * Any Postgres server process begins execution here.
56 : */
57 : int
58 3078 : main(int argc, char *argv[])
59 : {
60 3078 : bool do_check_root = true;
61 :
62 3078 : reached_main = true;
63 :
64 : /*
65 : * If supported on the current platform, set up a handler to be called if
66 : * the backend/postmaster crashes with a fatal signal or exception.
67 : */
68 : #if defined(WIN32)
69 : pgwin32_install_crashdump_handler();
70 : #endif
71 :
72 3078 : progname = get_progname(argv[0]);
73 :
74 : /*
75 : * Platform-specific startup hacks
76 : */
77 3078 : startup_hacks(progname);
78 :
79 : /*
80 : * Remember the physical location of the initially given argv[] array for
81 : * possible use by ps display. On some platforms, the argv[] storage must
82 : * be overwritten in order to set the process title for ps. In such cases
83 : * save_ps_display_args makes and returns a new copy of the argv[] array.
84 : *
85 : * save_ps_display_args may also move the environment strings to make
86 : * extra room. Therefore this should be done as early as possible during
87 : * startup, to avoid entanglements with code that might save a getenv()
88 : * result pointer.
89 : */
90 3078 : argv = save_ps_display_args(argc, argv);
91 :
92 : /*
93 : * Fire up essential subsystems: error and memory management
94 : *
95 : * Code after this point is allowed to use elog/ereport, though
96 : * localization of messages may not work right away, and messages won't go
97 : * anywhere but stderr until GUC settings get loaded.
98 : */
99 3078 : MemoryContextInit();
100 :
101 : /*
102 : * Set up locale information
103 : */
104 3078 : set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("postgres"));
105 :
106 : /*
107 : * In the postmaster, absorb the environment values for LC_COLLATE and
108 : * LC_CTYPE. Individual backends will change these later to settings
109 : * taken from pg_database, but the postmaster cannot do that. If we leave
110 : * these set to "C" then message localization might not work well in the
111 : * postmaster.
112 : */
113 3078 : init_locale("LC_COLLATE", LC_COLLATE, "");
114 3078 : init_locale("LC_CTYPE", LC_CTYPE, "");
115 :
116 : /*
117 : * LC_MESSAGES will get set later during GUC option processing, but we set
118 : * it here to allow startup error messages to be localized.
119 : */
120 : #ifdef LC_MESSAGES
121 3078 : init_locale("LC_MESSAGES", LC_MESSAGES, "");
122 : #endif
123 :
124 : /*
125 : * We keep these set to "C" always, except transiently in pg_locale.c; see
126 : * that file for explanations.
127 : */
128 3078 : init_locale("LC_MONETARY", LC_MONETARY, "C");
129 3078 : init_locale("LC_NUMERIC", LC_NUMERIC, "C");
130 3078 : init_locale("LC_TIME", LC_TIME, "C");
131 :
132 : /*
133 : * Now that we have absorbed as much as we wish to from the locale
134 : * environment, remove any LC_ALL setting, so that the environment
135 : * variables installed by pg_perm_setlocale have force.
136 : */
137 3078 : unsetenv("LC_ALL");
138 :
139 : /*
140 : * Catch standard options before doing much else, in particular before we
141 : * insist on not being root.
142 : */
143 3078 : if (argc > 1)
144 : {
145 3078 : if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
146 : {
147 0 : help(progname);
148 0 : exit(0);
149 : }
150 3078 : if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
151 : {
152 1248 : fputs(PG_BACKEND_VERSIONSTR, stdout);
153 1248 : exit(0);
154 : }
155 :
156 : /*
157 : * In addition to the above, we allow "--describe-config" and "-C var"
158 : * to be called by root. This is reasonably safe since these are
159 : * read-only activities. The -C case is important because pg_ctl may
160 : * try to invoke it while still holding administrator privileges on
161 : * Windows. Note that while -C can normally be in any argv position,
162 : * if you want to bypass the root check you must put it first. This
163 : * reduces the risk that we might misinterpret some other mode's -C
164 : * switch as being the postmaster/postgres one.
165 : */
166 1830 : if (strcmp(argv[1], "--describe-config") == 0)
167 0 : do_check_root = false;
168 1830 : else if (argc > 2 && strcmp(argv[1], "-C") == 0)
169 0 : do_check_root = false;
170 : }
171 :
172 : /*
173 : * Make sure we are not running as root, unless it's safe for the selected
174 : * option.
175 : */
176 1830 : if (do_check_root)
177 1830 : check_root(progname);
178 :
179 : /*
180 : * Dispatch to one of various subprograms depending on first argument.
181 : */
182 :
183 1830 : if (argc > 1 && strcmp(argv[1], "--check") == 0)
184 208 : BootstrapModeMain(argc, argv, true);
185 1622 : else if (argc > 1 && strcmp(argv[1], "--boot") == 0)
186 82 : BootstrapModeMain(argc, argv, false);
187 : #ifdef EXEC_BACKEND
188 : else if (argc > 1 && strncmp(argv[1], "--fork", 6) == 0)
189 : SubPostmasterMain(argc, argv);
190 : #endif
191 1540 : else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
192 0 : GucInfoMain();
193 1540 : else if (argc > 1 && strcmp(argv[1], "--single") == 0)
194 102 : PostgresSingleUserMain(argc, argv,
195 102 : strdup(get_user_name_or_exit(progname)));
196 : else
197 1438 : PostmasterMain(argc, argv);
198 : /* the functions above should not return */
199 : abort();
200 : }
201 :
202 :
203 :
204 : /*
205 : * Place platform-specific startup hacks here. This is the right
206 : * place to put code that must be executed early in the launch of any new
207 : * server process. Note that this code will NOT be executed when a backend
208 : * or sub-bootstrap process is forked, unless we are in a fork/exec
209 : * environment (ie EXEC_BACKEND is defined).
210 : *
211 : * XXX The need for code here is proof that the platform in question
212 : * is too brain-dead to provide a standard C execution environment
213 : * without help. Avoid adding more here, if you can.
214 : */
215 : static void
216 3078 : startup_hacks(const char *progname)
217 : {
218 : /*
219 : * Windows-specific execution environment hacking.
220 : */
221 : #ifdef WIN32
222 : {
223 : WSADATA wsaData;
224 : int err;
225 :
226 : /* Make output streams unbuffered by default */
227 : setvbuf(stdout, NULL, _IONBF, 0);
228 : setvbuf(stderr, NULL, _IONBF, 0);
229 :
230 : /* Prepare Winsock */
231 : err = WSAStartup(MAKEWORD(2, 2), &wsaData);
232 : if (err != 0)
233 : {
234 : write_stderr("%s: WSAStartup failed: %d\n",
235 : progname, err);
236 : exit(1);
237 : }
238 :
239 : /*
240 : * By default abort() only generates a crash-dump in *non* debug
241 : * builds. As our Assert() / ExceptionalCondition() uses abort(),
242 : * leaving the default in place would make debugging harder.
243 : *
244 : * MINGW's own C runtime doesn't have _set_abort_behavior(). When
245 : * targeting Microsoft's UCRT with mingw, it never links to the debug
246 : * version of the library and thus doesn't need the call to
247 : * _set_abort_behavior() either.
248 : */
249 : #if !defined(__MINGW32__) && !defined(__MINGW64__)
250 : _set_abort_behavior(_CALL_REPORTFAULT | _WRITE_ABORT_MSG,
251 : _CALL_REPORTFAULT | _WRITE_ABORT_MSG);
252 : #endif /* !defined(__MINGW32__) &&
253 : * !defined(__MINGW64__) */
254 :
255 : /*
256 : * SEM_FAILCRITICALERRORS causes more errors to be reported to
257 : * callers.
258 : *
259 : * We used to also specify SEM_NOGPFAULTERRORBOX, but that prevents
260 : * windows crash reporting from working. Which includes registered
261 : * just-in-time debuggers, making it unnecessarily hard to debug
262 : * problems on windows. Now we try to disable sources of popups
263 : * separately below (note that SEM_NOGPFAULTERRORBOX did not actually
264 : * prevent all sources of such popups).
265 : */
266 : SetErrorMode(SEM_FAILCRITICALERRORS);
267 :
268 : /*
269 : * Show errors on stderr instead of popup box (note this doesn't
270 : * affect errors originating in the C runtime, see below).
271 : */
272 : _set_error_mode(_OUT_TO_STDERR);
273 :
274 : /*
275 : * In DEBUG builds, errors, including assertions, C runtime errors are
276 : * reported via _CrtDbgReport. By default such errors are displayed
277 : * with a popup (even with NOGPFAULTERRORBOX), preventing forward
278 : * progress. Instead report such errors stderr (and the debugger).
279 : * This is C runtime specific and thus the above incantations aren't
280 : * sufficient to suppress these popups.
281 : */
282 : _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
283 : _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR);
284 : _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
285 : _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
286 : _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
287 : _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDERR);
288 : }
289 : #endif /* WIN32 */
290 3078 : }
291 :
292 :
293 : /*
294 : * Make the initial permanent setting for a locale category. If that fails,
295 : * perhaps due to LC_foo=invalid in the environment, use locale C. If even
296 : * that fails, perhaps due to out-of-memory, the entire startup fails with it.
297 : * When this returns, we are guaranteed to have a setting for the given
298 : * category's environment variable.
299 : */
300 : static void
301 18468 : init_locale(const char *categoryname, int category, const char *locale)
302 : {
303 18468 : if (pg_perm_setlocale(category, locale) == NULL &&
304 0 : pg_perm_setlocale(category, "C") == NULL)
305 0 : elog(FATAL, "could not adopt \"%s\" locale nor C locale for %s",
306 : locale, categoryname);
307 18468 : }
308 :
309 :
310 :
311 : /*
312 : * Help display should match the options accepted by PostmasterMain()
313 : * and PostgresMain().
314 : *
315 : * XXX On Windows, non-ASCII localizations of these messages only display
316 : * correctly if the console output code page covers the necessary characters.
317 : * Messages emitted in write_console() do not exhibit this problem.
318 : */
319 : static void
320 0 : help(const char *progname)
321 : {
322 0 : printf(_("%s is the PostgreSQL server.\n\n"), progname);
323 0 : printf(_("Usage:\n %s [OPTION]...\n\n"), progname);
324 0 : printf(_("Options:\n"));
325 0 : printf(_(" -B NBUFFERS number of shared buffers\n"));
326 0 : printf(_(" -c NAME=VALUE set run-time parameter\n"));
327 0 : printf(_(" -C NAME print value of run-time parameter, then exit\n"));
328 0 : printf(_(" -d 1-5 debugging level\n"));
329 0 : printf(_(" -D DATADIR database directory\n"));
330 0 : printf(_(" -e use European date input format (DMY)\n"));
331 0 : printf(_(" -F turn fsync off\n"));
332 0 : printf(_(" -h HOSTNAME host name or IP address to listen on\n"));
333 0 : printf(_(" -i enable TCP/IP connections (deprecated)\n"));
334 0 : printf(_(" -k DIRECTORY Unix-domain socket location\n"));
335 : #ifdef USE_SSL
336 0 : printf(_(" -l enable SSL connections\n"));
337 : #endif
338 0 : printf(_(" -N MAX-CONNECT maximum number of allowed connections\n"));
339 0 : printf(_(" -p PORT port number to listen on\n"));
340 0 : printf(_(" -s show statistics after each query\n"));
341 0 : printf(_(" -S WORK-MEM set amount of memory for sorts (in kB)\n"));
342 0 : printf(_(" -V, --version output version information, then exit\n"));
343 0 : printf(_(" --NAME=VALUE set run-time parameter\n"));
344 0 : printf(_(" --describe-config describe configuration parameters, then exit\n"));
345 0 : printf(_(" -?, --help show this help, then exit\n"));
346 :
347 0 : printf(_("\nDeveloper options:\n"));
348 0 : printf(_(" -f s|i|o|b|t|n|m|h forbid use of some plan types\n"));
349 0 : printf(_(" -O allow system table structure changes\n"));
350 0 : printf(_(" -P disable system indexes\n"));
351 0 : printf(_(" -t pa|pl|ex show timings after each query\n"));
352 0 : printf(_(" -T send SIGABRT to all backend processes if one dies\n"));
353 0 : printf(_(" -W NUM wait NUM seconds to allow attach from a debugger\n"));
354 :
355 0 : printf(_("\nOptions for single-user mode:\n"));
356 0 : printf(_(" --single selects single-user mode (must be first argument)\n"));
357 0 : printf(_(" DBNAME database name (defaults to user name)\n"));
358 0 : printf(_(" -d 0-5 override debugging level\n"));
359 0 : printf(_(" -E echo statement before execution\n"));
360 0 : printf(_(" -j do not use newline as interactive query delimiter\n"));
361 0 : printf(_(" -r FILENAME send stdout and stderr to given file\n"));
362 :
363 0 : printf(_("\nOptions for bootstrapping mode:\n"));
364 0 : printf(_(" --boot selects bootstrapping mode (must be first argument)\n"));
365 0 : printf(_(" --check selects check mode (must be first argument)\n"));
366 0 : printf(_(" DBNAME database name (mandatory argument in bootstrapping mode)\n"));
367 0 : printf(_(" -r FILENAME send stdout and stderr to given file\n"));
368 :
369 0 : printf(_("\nPlease read the documentation for the complete list of run-time\n"
370 : "configuration settings and how to set them on the command line or in\n"
371 : "the configuration file.\n\n"
372 : "Report bugs to <%s>.\n"), PACKAGE_BUGREPORT);
373 0 : printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
374 0 : }
375 :
376 :
377 :
378 : static void
379 1830 : check_root(const char *progname)
380 : {
381 : #ifndef WIN32
382 1830 : if (geteuid() == 0)
383 : {
384 0 : write_stderr("\"root\" execution of the PostgreSQL server is not permitted.\n"
385 : "The server must be started under an unprivileged user ID to prevent\n"
386 : "possible system security compromise. See the documentation for\n"
387 : "more information on how to properly start the server.\n");
388 0 : exit(1);
389 : }
390 :
391 : /*
392 : * Also make sure that real and effective uids are the same. Executing as
393 : * a setuid program from a root shell is a security hole, since on many
394 : * platforms a nefarious subroutine could setuid back to root if real uid
395 : * is root. (Since nobody actually uses postgres as a setuid program,
396 : * trying to actively fix this situation seems more trouble than it's
397 : * worth; we'll just expend the effort to check for it.)
398 : */
399 1830 : if (getuid() != geteuid())
400 : {
401 0 : write_stderr("%s: real and effective user IDs must match\n",
402 : progname);
403 0 : exit(1);
404 : }
405 : #else /* WIN32 */
406 : if (pgwin32_is_admin())
407 : {
408 : write_stderr("Execution of PostgreSQL by a user with administrative permissions is not\n"
409 : "permitted.\n"
410 : "The server must be started under an unprivileged user ID to prevent\n"
411 : "possible system security compromises. See the documentation for\n"
412 : "more information on how to properly start the server.\n");
413 : exit(1);
414 : }
415 : #endif /* WIN32 */
416 1830 : }
417 :
418 : /*
419 : * At least on linux, set_ps_display() breaks /proc/$pid/environ. The
420 : * sanitizer library uses /proc/$pid/environ to implement getenv() as it wants
421 : * to work independent of libc. When just using undefined and alignment
422 : * sanitizers, the sanitizer library is only initialized when the first error
423 : * occurs, by which time we've often already called set_ps_display(),
424 : * preventing the sanitizer libraries from seeing the options.
425 : *
426 : * We can work around that by defining __ubsan_default_options, a weak symbol
427 : * libsanitizer uses to get defaults from the application, and return
428 : * getenv("UBSAN_OPTIONS"). But only if main already was reached, so that we
429 : * don't end up relying on a not-yet-working getenv().
430 : *
431 : * As this function won't get called when not running a sanitizer, it doesn't
432 : * seem necessary to only compile it conditionally.
433 : */
434 : const char *__ubsan_default_options(void);
435 : const char *
436 0 : __ubsan_default_options(void)
437 : {
438 : /* don't call libc before it's guaranteed to be initialized */
439 0 : if (!reached_main)
440 0 : return "";
441 :
442 0 : return getenv("UBSAN_OPTIONS");
443 : }
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